Release coatings used in durable, stain resistant, heat resistant or erasable materials as well as in release papers typically include silicone containing materials or other release agents to provide the release properties. However, the silicone groups, and particularly siloxane groups (e.g., PDMS, organo-silicones, reactive silicones like acrylate functional materials, etc.), in typical silicone release coatings can lead to severe contamination problems. Since the typical siloxane release agents in coatings are present as low molecular weight materials before curing, at this stage they are not anchored into the coating and can transfer to coating equipment and then to other materials subsequently processed on the equipment. The siloxane release agents have a low surface tension and low viscosity and thus tend to easily spread onto the equipment and then onto other materials processed on the equipment. This contamination is difficult to remove and contaminated materials such as films or papers contaminated with the siloxanes have very low surface energy spots which cause voids in coatings applied to them and poor adhesion of coatings, inks or adhesives. Once the coatings are cured, the siloxanes should be firmly anchored; however, the cured silicone release coatings have another disadvantage: in certain applications, it is desirable to apply inks or other coatings onto the release coatings and then remove such inks or coatings sometime later. For example, one might want to apply a coating or an ink to the release coating and then transfer the coating or ink to another material such as a garment at a later date, or one might want to use the release coating as an erasable substrate. However, due to the very low surface energy of typical siloxane containing release coatings, subsequently applied coatings or inks will not spread evenly and tend to bead on the surface. Additionally, coatings containing silicone release agents cannot be conveniently coated with water based acrylic or polyurethane polymers due to the low surface energy of these release coatings.
Although siloxane containing release coatings do pose problems, they are very effective and their effectiveness in many applications has not been matched by other types of release coatings. Thus, a need exists for effective durable, heat resistant and erasable release coatings which contain no siloxane release agents. Additionally, a need exists for release coatings which can be effectively printed or over coated with inks or coatings which are subsequently removable. Also, there is a need for durable, graffiti resistant and erasable materials. In addition, heat transfer papers and heat transfer decals which have internal release coatings and releasably attached polymeric coatings, such as polyurethane and acrylic polymer coatings, are desired for transfer of durable, stretchable graphics and also for transfer of textures.